中苜一号紫花苜蓿碳同化分配与转移速率的研究

对紫花苜蓿(Medicago sativa L.)(中苜一号)的生长条件进行控制,并在分枝期对其进行¹³C脉冲标记,收集标记后第6,12,18,24,30 d的叶、茎、根以及土壤样品,测定各样品中¹³C含量,以此来探讨苜蓿光合碳的吸收与转移。结果表明:苜蓿各组分光合产物的分配顺序为茎>叶>根;¹³C转移速率为叶>茎>根,随着时间的延长,苜蓿各组分¹³C含量逐渐减少,最终达到稳定状态;渗漏到土壤中的¹³C含量在0~10 cm土壤层显著高于10~20 cm,但10~20 cm的¹³C含量比较稳定。     

典型草原恢复演替过程中土壤微生物及酶活性动态变化研究

选取不同围封年限的生长季围封恢复草地为研究对象,开展典型草原恢复演替过程中土壤微生物及酶活性动态变化的研究,探讨土壤微生物及酶活性与草地植被及土壤养分的相关性。结果表明:与自由放牧草地相比,围封7年、10年、13年和20年的草地,其土壤0~30 cm土层细菌、放线菌和真菌数量显著增加,土壤转化酶、脲酶、蛋白酶和过氧化氢酶活性增强,土壤微生物量碳、氮含量显著增加(P<0.05),且随围封年限的延长呈增加的变化趋势。典型草原恢复演替过程中土壤微生物及酶活性与草地植被及土壤养分呈基本一致的变化规律,三者成密切的正相关关系。     

餐厨垃圾堆肥过程中水解酶活性变化的研究

为了研究餐厨垃圾在静态强制通风条件下堆腐过程的矿质化进度和强度。以小麦秸秆作为膨松剂,比较了不同C/N比（20,25,30）条件下餐厨垃圾堆肥过程中各个阶段纤维素酶、蔗糖酶、脲酶、蛋白酶4种水解酶活性的变化情况。结果表明,不同C/N比处理的温度变化趋势基本相同,40℃以上高温期持续达10天左右。25C/N和30C/N堆肥条件下的纤维素酶活整体比20C/N要高,酶活高峰期出现滞后于温度高峰期;不同C/N条件下,蔗糖酶活性变化趋势基本相似,酶活高峰期与温度高峰期同步;30C/N条件下的脲酶活性峰值出现早于20C/N和25C/N,最终脲酶活性下降到比堆肥初期还要低的程度;高温对蛋白酶活性有抑制作用,25C/N条件下蛋白酶活性峰值出现晚于其他2个处理。从试验结果可以看出,不同营养条件下同类酶活性的变化趋势表现出一定的差异,与堆肥过程中有机物质的转化密切相关,可以作为判断堆肥腐熟度的因素之一。     

不同沼肥用量对番茄产量和品质的影响

摘 要 本研究于2010-2011年进行,通过沼肥田间试验,研究了不同沼肥施用量对番茄株高、单株结果数、果实成熟率、成熟单果质量、产量和品质的影响。结果表明：随着沼肥用量的增加,番茄的株高、单株结果数均有明显改善,但番茄果实成熟率以及成熟果实平均单果质量却呈现先增加后降低。在T4(沼肥52500 kg·hm-2+磷酸二铵300 kg·hm-2)处理时番茄产量达到最高,为84375 kg·hm-2。番茄中Vc、可溶性总糖的含量在随着沼肥用量增加而呈现单峰曲线变化,最高值均出现在T5(沼肥60000 kg·hm-2+磷酸二铵300 kg·hm-2)处理,分别为127.37 mg·kg-1和6.03%。番茄中硝酸盐的含量却随着沼肥用量的增加呈明显上升的趋势。     

响应面法优化超临界CO2萃取金柑籽中柠檬苦素工艺条件的研究

优化超临界CO2萃取柠檬苦素的工艺条件,为金柑籽中柠檬苦素的开发提供理化依据。采用单因素试验研究夹带剂、夹带剂浓度、萃取温度、萃取时间、萃取压力和二氧化碳流量对柠檬苦素提取率的影响,在单因素试验的基础上,采用响应面分析法建立了二次多项式数学模型,并分析模型的有效性与各因素间的交互作用。在萃取压力为33 MPa,萃取温度为50℃,萃取时间为2.5 h的条件下,柠檬苦素提取率达3.98 g/kg。在最佳条件下得到实验结果与模型预测值吻合,说明所建立的模型是切实可行的。超临界CO2萃取技术的运用,有利于柠檬苦素提取的工业化推广和应用。     

Isolation and pathogenicity of Colletotrichum spp. causing anthracnose of strawberry in south west Spain

Anthracnose, caused by Colletotrichum spp., is a major disease of cultivated strawberry, Fragaria × ananassa. This study identifies the Colletotrichum spp. which causes strawberry anthracnose in the southwest of Spain. A survey of the region was carried out, and the strains isolated were identified as C. acutatum by using the polymerase chain reaction (PCR) with genus and species-specific primers, demonstrating that this species is currently the causal agent of strawberry anthracnose in the studied region. The pathogenicity of C. acutatum and C. gloeosporioides strains was evaluated on two principal strawberry cultivars (cvs Camarosa and Ventana) under field conditions, the latter being more pathogenic than the former.     

Impact of sodium cyanide on catalase activity in the freshwater exotic carp, Cyprinus carpio (Linnaeus)

The Cyprinus carpio fingerlings on exposure to lethal (1 mg/L) and sub lethal concentrations (0.066 mg/L) of sodium cyanide showed inhibition in the activity of catalase. The disruption of catalase activity in freshwater fish, C. carpio is demonstrated in the present study using UV–visible spectrophotometer at 240 nm using hydrogen peroxide as a substrate. It suggests toxic effects of sodium cyanide and consequent accumulation of hydrogen peroxide in the functionally different tissues namely, liver, gill, muscle and brain. This might lead to cellular damages, and create widespread physiological disturbance. The results suggest that catalase activity can be a good diagnostic tool for sodium cyanide toxicity in biomonitoring programme.     

文蛤C1q基因的克隆与表达及其重组蛋白活性的研究

利用构建的文蛤cDNA文库,克隆得到了文蛤C1q基因全长cDNA序列,该序列全长1213bp,5′UTR为316bp,3′UTR为372bp,开放阅读框长度为525bp,编码174个氨基酸。在文蛤C1q(MmC1q)蛋白中,C1q结构域与软体动物、两栖类动物和脊椎动物中的C1q结构域均具有较高的同源性。通过荧光实时定量PCR,MmC1q mRNA在所检测的各个组织中均有表达,在肝胰脏中表达量最高。在细菌感染试验中,文蛤受鳗弧菌感染后,C1q相对表达水平有明显的上升调节,注射2h,MmC1qmRNA表达量最高,为对照组的2.19倍。包含成熟肽的MmC1q cDNA片段被重组,并在大肠杆菌BL21(DE3)中表达,采用牛津杯法对MmC1q重组蛋白进行体外抑菌试验,但并未检测到明显的抑菌活性。     

Fecundity of the sea louse Caligus rogercresseyi on its native host Eleginops maclovinus captured near salmon farms in southern Chile

The sea louse (Caligus rogercresseyi) is the most significant parasitic pathogen in Chilean salmon farms, and it infects farmed salmon and native host fish. Fecundity is one of the most important parameters for understanding the population dynamics of a species; however, this information is scarce for this parasite. The fecundity of C. rogercresseyi females collected from native hosts (Eleginops maclovinus) captured near salmon farms in southern Chile was measured to evaluate the reproductive output of this parasite on this host fish. From June 2008 to May 2009, 212 specimens of E. maclovinus were examined. Each fish was measured, and all its parasites were collected, sorted and counted. Seventy‐nine ovigerous C. rogercresseyi females (OFs) were measured. Total body length, egg string length and total number of eggs per string were recorded for each parasite. Ovigerous females body length varied between 3.9 and 5.0 mm. Fecundity varied between 12 and 56 eggs string^?1, and it was correlated with OF body length. Temporal variations in OF fecundity were explained by co‐variation in OF body length, but not by month. Ovigerous females on E. maclovinus were smaller and showed lower fecundity than OFs on farmed salmon. Our results suggest that native hosts play a secondary role in C. rogercresseyi egg production in Codigue bay.     

Dietary reduction of fish meal,supplementation of vitamin C and fish oil may promote ovary maturation by improving digestibility and immunity in Procambarus clarkii (Crustacea: Decapoda)

Fish meal, vitamin C and fish oil are known to play essential roles in reproduction and immunity in animals. To investigate how the diet affect reproduction under the condition of reducing costs, we designed an experimental diet that decreased the ratio of fish meal with soybean meal from 1:1 to 1:1.5, and supplemented with 0.06% vitamin C and 3.8% fish oil for the crayfish, Procambarus clarkii. After a 100‐day feeding experiment, female crayfish fed the test diet had significantly greater gonadosomatic index (GSI) compared with those fed the basal diet (P < 0.05). At the middle stage of ovarian development, the test diet gave significantly higher trypsin‐specific activity (340.94 ± 57.32 U mg^?1 protein) in hepatopancreas of the crayfish than the basal diet (89.48 ± 10.01 U mg^?1 protein) (P < 0.05). However, hepatosomatic index (HSI) was remarkably decreased for those females fed test diet (P < 0.05). In addition, the experimental diet resulted in markedly lower superoxide dismutase (SOD) activity and malonaldehyde (MDA) levels, especially in the ovaries (P < 0.01). These results suggest that dietary reduction of fish meal, supplementation of appropriate amounts of vitamin C and fish oil may promote ovary development probably by increasing digestibility, as well as by promoting transferring of nutrients from hepatopancreas to ovary and raising immunity of P. clarkii.